Gem-dinitro carbamates



United States Patent GEM-DINITRO CARBAMATES Karl Klager, Monrovia, Califl, assignor to Aeroiet- General Corporation, Azusa, Califl, a corporation of Ohio No Drawing. Filed July-15,1957, Ser. No. 672,540 A 20 (Cl.260482) This invention relates to new compositions of matter and a method for their preparation. In particular, it relates to carbamates having the general formula:

wherein R and R are the same or diflerent alkyl groups, and A is an alkylene group.

This application is a continuation-in-part of my copending application, Serial No. 426,901, filed April 30, 1954, now abandoned. I l

The new compositions of my invention readily undergo hydrolysis to yield their corresponding amino acids, as disclosed in my copending United States patent application, Serial No. 672,539, filed concurrently herewith. The amino acids thus produced readily react with B-geminal polynitroalcohols such as dinit'roethanol to produce their corresponding esters. 'The esters thus produced are excellent high explosives and can be used in anyconventional explosive missile, projectile, rocket, or the like, as the main explosive charge. An example of such a missile is disclosed in United States Patent No. 2,470,162, issued May 17, 1949. One way of using the high explosives in a device such as that disclosed in United States Patent No. 2,470,162 is to .pack the crystalline explosive in powder form into the warhead of the missile. Alternatively, the crystals can be first pelletized' and then packed. A charge thus prepared is sufiiciently insensitive to withstand the shock entailed in the ejection of a shell from a I gun barrel or from a rocket launching tube under the pressure developed from ignition of a propellant charge, and can be caused to explode on operation; of an impactor time-fuse mechanism firing a detonating explosive such as lead azide or mercury fulminate.

The compounds of the present invention are conveniently prepared by reacting a carboalkoxynitro-containing acid halide with an azide of an alkali or alkaline earth metal and subsequently heating under anhydrous conditions in the presence or an alcohol, in accordance with wherein X is a halogen radical, M is an alkali or alkaline earth metal radical, and R, R and A are as defined above.

The carboalkoxy nitro-containing acid halides employed as starting materials in this invention are prepared by reacting the corresponding acid'with a thionyl halide or a phosphorous halide. The acids areobtained by the condensation of the' nitronate salt of a nitro-containing e'ster with a labile hydrogen-containing acid, e.g. acrylic ice acid. The reactive carbonyl centers may be reversed in the starting material by condensing the nitronate salt of a nitro-containing acid with a labile hydrogen-containing ester, e.g. methyl acrylate. By condensing appropriate nitronate salts of acids and esters with labile hydrogencontaining acids and esters and reacting the condensation product with a thionyl halide, a wide variety of carboalkoxy nitro-containing acid halides are available as starting materials. for the preparation of the amides of this invention. p i

To more fully illustrate this invention, the following examples are presented. It is to be understood, however, that these examples are presented merely as a means of illustration and are notintended to limit the scope of the invention in any way.

EXAMPLE I 7 Preparation of dimethyl 4,4-dinitr0-7-aza-0 ctanedi0ate A mixture of 30 gm. 6-carbomethoxy-4,4-dinitrohexa noic acid and 100 ml. freshly distilled thionyl chloride was refluxed'for 5 hours in a three-necked flask provided with a stirrer, reflux condenser and thermometer. After allowing the; mixture to stand'overnight, the excess of thionyl chloride was removed in vacuo to yield 35.5 gm. of'a honey-like oil, the 6-carbomethoxy-4,4-dinitrohexanoyl chloride. Without further purification this acid chloride was dissolved in 50 ml. acetone and dropped into a solution of 15 gm. sodium azide in 100 ml. water at a temperature of 20-25", C., within a period of 3 minutes. Stirring was then continued for minutes at the same temperature. a The water phase was extracted with chloroform and the extract was washed with aqueous'sodium bisulfite, then dried and filtered. After adding mlxof methanol the solution was refluxed for 60 minutes. The chloroform-methanol solution was then concentrated in vacuo until crystals formed. The crystalline dimethyl 4,4-dinitro-7-aza-octanedioate was collected on a Buchne'r funnel and washed with cold ether. After 2 recrystallizations from methanol and 1 recrystallization from isopropyl ether, 22'- gm. of colorless prisms were obtained, M.P. 75 C. "The elemental analysis of'the product is as follows. j

Calculated for C H 5N O Percent C, 36.86; percent H, 5,15. lFoundrPercent C, 37.10; percent H, 5.22.

EXAMPLE II 7 Preparation of ethyl 7-carbomethoxy-5 ,5 -dinitrO-2-azah e ptalio ate' Ethyl 7-carbomethoxy-5,5-dinitro-2-azo-heptanoate was prepared by reacting 6-carbomethoxy-4,4-dinitrohexanoyl chloride with sodium azide according to the procedure described in Example I. The chloroform mixture was mixed with 50 ml. of ethanol and slowly heated to reflux. After the evolution: offnitrogeni ceased the heating was continued for 60 minutes. The solvent was then removed by evaporation, in vacuo leaving a creamy coloredoil which crystallized upon prolonged standing. The crystals were dissolved in absolute ether, decolorized with charcoal and cooled to 20 C. Upon addition of hexane, white crystals, M.P. 39 C., formed.

EXAMPLE 1n Preparation of propyl Zcarbomethoxy-iidinitro-Z-gza v ".he pt'ahoate a melting point"of70- 7'1.5 C.

Butyl 7-carbomethoxy-5,5-dinitro-2-aza heptanoate was prepared by reacting 6-carbomethoxy-4,4-dinitrohexanoyl chloride with sodium azide according to the procedure described in Example I, and heating the resulting organic 'azide in the presence of butanol. The product, recrystallized from a mixture of ether and hexane, had a melting point of 3030.5 C.

' The reaction temperatures used in the above examples are completely arbitrary and were selected purely for reasons of convenience. Both higher and lower temperatures can be used without afiecting the course of the reaction. V I

While any of the alkali and alkaline earth metal azides, such as magnesium, potassium, etc. azides, can be used in the practice of my invention, sodium azide is preferred for reasons of cost and availability.

Other members in the new classofcompounds of my invention can be prepared by proceeding in accordance with the general reaction scheme and the specific ex amples presented above. For example, propyl 2-aza-5,5- dinitro-7-carboethoxyheptanoate is prepared by reacting 4,4-dinitro-6 -carboethoxy hexanoyl bromide with sodium azide in the presence of propane]; isopropyl 2-aza-4,4- dinitro-6-carboisopropoxy hexanoate is. prepared by reacting 3,3-dinitro--carboisopropoxy pentanoyl chloride with sodium azide followed by heating in the presence of isopropanol; n-butyl 2-aza-4,4-dinitro--carbopropoxy hexanoate is prepared by reacting 3,3-dinitro-5-carbopropoxy pentanoyl chloride with sodium azide followed by heating in the presence of butanol; ethyl 2-aza-5,5-dinitro-8-carboethoxy octanoate is prepared by reacting 4,4- dinitro-7-carboethoxy heptanoyl chloride with sodium azide followed by heating in the presence of ethanol;

methyl 2-aza-5-nitro-7-carbomethoxy heptanoate is prepared by reacting 4-nitro-6-carbomethoxy hexanoyl chloride with sodium azide followed by heating in the presence of methanol; and methyl 2-aza-5-methyl-5-nitro-9- 'carboethoxy nonanoate is prepared byreacting 4-methyl- 4-nitro-8-carboethoxy octanoyl chloride with sodium azide followed by heating in the presence of methanol.

It is apparent from the above discussion that any member of the carboalkoxy aza-nitro ester series disclosed may be prepared by merely reacting an appropriate carboalkoxy-nitro acid in accordance with the'teachings of this invention.

I claim:

1. As new compositions of matter, the nitro-containing carbamates having the general formula:

oxy-5,5-dinitro-2-aza-heptanoate having the structural formula:

' 4. As a new composition of matter, propyl 7 carbo- 4, i methoxy-S,S-dinitro-Z-aza-heptanoate having the structural formula:

5. As a new composition oi matter, butyl 7-carbomethoxy-5,5 dinitro-Z-Z-aza-heptanoate having the structural formula:

. H Nos E!) omorno'momoo-NH-omom bomotn-o-oont 6. As a new .compositionof matter, propyl 2-aza-5,5- dinitro-7-carboethoxy-heptanoate having the structural formula:

7. As a new composition of matter, isopropyl 2-aza- 4,4-dinitro-6-carboisopropoxy-hexanoate having the structural formula:

8. As a new composition of matter, n-butyl. :2-aza-4,4 dinitro-6-carbopropoxy-hexanoate having the structural formula:

9. As a new composition of matter, ethyl 2-aza-5,5- dinitro-S-carboethoxy-octaanoate having the structural formula:

10. As a new composition of matter, methyl 2-aza-5- nitro-7-carbomethoxy-heptanoate having the structural formula:

N 02 ll oH3oc-NHoHi0HioHoHlCHr-ii-O0H3 11. As a new composition of matter, methyl 2-aza-5- methyl 5-nitro-Q-carbQethoXy-nonanoate having the structural formula: I

u i n oHPo-o-NHcmoHt-c i emaroon:0H1-0-00H10Ht on; i A

12. The method of preparing nitro-containing'. carbamates having the general formula:

which comprises reacting an organic acid halide having the general formula:

oxy-4,4-dinitrohexanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of methanol.

14. The method of preparing ethyl 7-carbomethoxy- 5,5-dinitro-2-aza-heptanoate which comprises reacting 6- carbomethoxyt,4-dinitrohexanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of ethanol.

15. The method of preparing propyl 7-carbomethoxy- 5,5-dinitro-2-aza heptanoate which comprises reacting 6- carbomethoxy-4,4-dinitrohexanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of propanol.

16. The method of preparing butyl 7-carbomethoxy- 5,5-dinitro-2-aza-heptanoate which comprises reacting 6- carbomethoxy-4,4-dinitrohexanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of butanol.

17. The method of preparing propyl 2-aza-5,5-dinitro- 7-carboethoxy which comprises reacting 4,4-dinitro-6- carboethoxy hexanoyl bromide with sodium azide, and subsequently heating the resultant organic azide in the presence of propanol.

18. The method of preparing isopropyl 2-aza-4,4-dinitro-6-carbois0propoxy hexanoate which comprises reacting 3,3-dinitro-5-carboisopropoxy pentanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of isopropanol.

19. The method of preparing n-butyl 2-aza-4,4-dim'- tr0-6-carbopropoxy hexanoate which comprises reacting 3,3-dinitro-5-carbopropoxy pentanoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of n-butan0l.

20. The method of preparing ethyl 2-aza-5,5-dinitro- 8-carboethox'y octanoate which comprises reacting 4,4-dinitro-7-carboethoxy hept-anoyl chloride with sodium azide and subsequently heating the resultant organic azide in the presence of ethanol.

No references cited. 

1. AS NEW COMPOSITIONS OF MATTER, THE NITRO-CONTAINING CARBAMATES HAVING THE GENERAL FORMULA: 